I just sold a monthly subscription to Liist.io by cold emailing someone.
I found Dan's post about CasterKit on IH late one night. As someone on the cusp of launching my own podcast, I checked it out and realized this was the perfect use case for Liist.
I cold emailed Dan that night explaining what Liist is and linked to a few examples. Before hitting send, I took 20 minutes to whip up a mockup based on the logo and added it as an attachment. Dan would later say "your email was almost the perfect sales email".
Check out the site at https://casterkit.com